SB-102B is used with digital top set and is composed of 2 units, the master unit used with another affiliated unit to distribute signal to a second TV and if you want to distribute the digital signal to more TV terminals, then you only have to increase the affiliates.For example: you have 3 (or more) TV terminals in house,then you only have to buy one master and 3 affiliates (or more).The master model No.is SB-102B and the affiliate No.SB-102B2.You can use the same digital top set remote for different TVs.The cable frequency synchronization technology is utilized which features: 1.forward frequency....5-56MHz 2.back frequency....87-1000MHz 3.RF output channels... 04CH/05CH/(VL band) 4.sound carrier wave frequency.......6.5MHz 5.-RF distance......>=100m 6.-IR distance......>=00m